Effect of Waste Cooking Oil Biodiesel Blends on Performance and Emissions from a CRDI Diesel Engine

Abstract

The employment of biofuels in blends with diesel oil proved to attain a reduced environmental impact without compromising the engine performance. Among biofuels, waste cooking oil offers the advantages of its reduced raw material cost in comparison with fresh vegetable oil cost; it also eliminates the environmental impacts caused by its disposal. Although a great number of researches has been devoted to biodiesel combustion in engines and pollutant emissions, few studies can be found on light duty diesel engine equipped with up-to-date technologies. This work aims at investigating the impact of waste cooking oil percentage in blends with diesel oil on the performance and emission characteristics of an up-to-date light and compact common rail diesel engine whose main application is in microcars and in urban vehicles. A comprehensive experimental activity was performed in the engine complete operative field. The comparison of the results with those obtained with standard ultralow-sulfur diesel highlighted that the engine performance was quite similar for B20 and diesel oil. B40 suffered for the lower caloric value in regard to diesel. A reduction in CO and HC was obtained with biodiesel blends, along with an increase in NO x . Particulate emissions were also reduced for biodiesel blends; the mean size of particles was smaller as regards diesel oil.

Effect of Waste Cooking Oil Blending with Diesel Fuel on Tractor Engine Performances and Exhaust Gases Emission

“…Based on the results obtained in this study, as well as the results of other authors, can be concluded that engine performances and exhaust emissions of diesel engine depend not only on the type of fuel but also on the engine technical characteristics such as compression ratio [26], fuel injection system [22], ignition type [12,16], injection pressure [30], as well as the engine operating mode (load and speed).…”

“…The lowest torque values at all measurement points and significantly lower (P˂0.05) average engine torque were achieved using a B20 blend, while between other fuels there were no significant differences (P˂0.05) in engine torque. Chiatti et al [22] showed the variation of engine torque with speed at fullload condition for diesel fuel and blends with 20% and 40% WCO and concluded that the torque trend at fullload condition depends on the proportion of WCO in the fuel; since WCO has a lowering heating value than diesel fuel. With that are agree [20], with additional opinion that high engine torque with pure diesel is due to the fact that the density of WCO blend is higher than that of the pure diesel fuel, therefore a larger mass flow at low engine speeds engine torque increases with the higher proportion of WCO, while at high engine speeds the modified operation of a mechanical governor is observed and the governor starts to reduce injected fuel quantity earlier when the higher proportion of WCO is used and engine torque decrease faster.…”

“…The significantly lower (P˂0.05) average specific fuel consumption was achieved using D100 fuel and B10 blend compared to B20 and B30 blends. Chiatti et al [22] reported that the specific fuel consumption increases with the content of WCO in the fuel and the average increase over all engine speed values is 3.9% for B20 and 7.1% for B40 blend, while [23] reported even 11.69% higher specific fuel consumption of B20 blend than D100 diesel fuel. According to [8], the differences in specific fuel consumption may be a consequence of the higher density and lower calorific value of the blended fuels compared to diesel fuel.…”

“…The lower NO x emission of pure diesel fuel than diesel fuel blended with WCO was also reported by [15,23,27], who explain that increase in NO x emission for WCO blends was due to increase of oxygen content in blends and higher cylinder temperature compared to diesel fuel. In addition to the effect of temperature, the increase in NO x emission can be explained by considering the differences in fuel chemistry, spray properties, and ignition delay that affect the duration of premixed and diffusion burn regimes [22]. On the contrary, [25,28] reported lower NO x emission of WCO blends and attributed this with lower temperature in the combustion chamber temperatures a reason for that they considered relatively lower carbon content in the same volume of fuel consumed at the same engine load.…”

Performance Optimization of Compression Ignition Engines: A Review

“…The use of waste oil biodiesel in com pression ignition engines results in im proved emission characteristics with th e exception of NOx and CO2. [41][42][43].…”